Publications by authors named "Inês M Valente"

14 Publications

  • Page 1 of 1

Response of Solanum lycopersicum L. to diclofenac - Impacts on the plant's antioxidant mechanisms.

Environ Pollut 2020 Mar 9;258:113762. Epub 2019 Dec 9.

GreenUPorto - Sustainable Agrifood Production Research Centre, Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, 4169-007, Porto, Portugal.

One emerging problem that recently has become a vastly acknowledged topic of concern is the environmental contamination by pharmaceuticals. Diclofenac (DCF) is one of the most common pharmaceuticals found, due to its high utilization and low removal rate in wastewater treatment processes. In this work, Solanum lycopersicum L. was used as a model to unravel how DCF contamination can affect crops, focusing on the internal mechanisms triggered by this exposure. For this purpose, plants were exposed to two different DCF concentrations (0.5 mg L and 5 mg L). Results obtained here point towards a loss of shoot performance when plants were exposed to very high concentrations of DCF, but no delay or loss of yield in the flowering and fruit stages were ascribed to DCF contamination. Our data shows that a state of oxidative stress due to high reactive oxygen species accumulation was associated with this contamination, with very high DCF levels leading to a rise of lipid peroxidation, possibly accentuated by the inhibition of ROS-scavenging enzymes and unable to be counteracted by the visible upregulation of proline and the thiol-based redox network. Overall, these results allow to infer that in the current environmental context, no noticeable negative effects should be associated with the presence of DCF in soils where this crop is cultivated. However, the oxidative stress and lower biomass associated with the highest concentration are alarming, since DCF levels in the environment are continuously increasing and further measures are necessary to assess this problematic.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.envpol.2019.113762DOI Listing
March 2020

Unravelling the phytonutrients and antioxidant properties of European Vicia faba L. seeds.

Food Res Int 2019 02 10;116:888-896. Epub 2018 Sep 10.

REQUIMTE, LAQV, ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.

For the first time, seven European varieties of Vicia faba L. seeds were investigated for (1) their phytonutrients profile by HPLC-DAD-MS/MS, (2) total phenolic content (TPC), and (3) antioxidant capacity (DPPH and FRAP assays). A wide range of compounds were identified, namely alkaloids, organic acids, terpenoids, jasmonates, and phenolics; these two latter being the most abundant. TPC ranged between 2.62 and 4.3 mg (gallic acid equivalent) g dry weight, for V. faba major variety Belshi and V. faba minor variety Bauska, respectively. The DPPH radical scavenging capacity showed poor correlation (r = 0.550, P = .041) with TPC, suggesting the presence of other antioxidant sources than phenolics. Still, FRAP was positively correlated with TPC (r = 0.709, P < .01) and DPPH (r = 0.819, P < .01). These results elucidated the phytonutrients and antioxidant properties of V. faba L. seeds as functional food sources.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.foodres.2018.09.025DOI Listing
February 2019

Profiling of phenolic compounds and antioxidant properties of European varieties and cultivars of Vicia faba L. pods.

Phytochemistry 2018 Aug 21;152:223-229. Epub 2018 May 21.

REQUIMTE, LAQV, ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal.

Vicia faba L. pods are a by-product generated from the industrial processing of beans for human and animal consumption. As phenolic compounds may play important roles in health, the present work envisaged the phenolic characterization of seven European varieties and cultivars of V. faba (major and minor) pods and the assessment of their antioxidant activity. The V. faba methanolic extracts were characterized by HPLC-DAD-MS/MS for identification of polyphenolic compounds. The total phenolic content and antioxidant capacity of the extracts were evaluated by colorimetric methods (Folin-Ciocalteu, DPPH scavenging capacity assay, and FRAP assay). Main compounds identified by HPLC-DAD-MS/MS were derivatives of caffeic acid, coumaric acid and kaempferol. The broad bean Jögeva variety presented the highest content of free and esterified phenolics (26.3 and 26.7 mg 100 g dry weight, respectively), followed by the horse bean varieties Bauska and Lielplatones. These results were corroborated by the analysis of total phenolic content, DPPH scavenging capacity and FRAP. This study confirmed the rich phenolic content of V. faba pods suggesting to be an interesting novel source for animal nutrition, promoting product quality and consumers' health.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.phytochem.2018.05.011DOI Listing
August 2018

Qualitative carbonyl profile in coffee beans through GDME-HPLC-DAD-MS/MS for coffee preliminary characterization.

Food Res Int 2018 05 1;107:536-543. Epub 2018 Mar 1.

REQUIMTE/LAQV - Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.

In this work, an analytical methodology for volatile carbonyl compounds characterization in green and roasted coffee beans was developed. The methodology relied on a recent and simple sample preparation technique, gas diffusion microextraction for extraction of the samples' volatiles, followed HPLC-DAD-MS/MS analysis. The experimental conditions in terms of extraction temperature and extraction time were studied. A profile for carbonyl compounds was obtained for both arabica and robusta coffee species (green and roasted samples). Twenty-seven carbonyl compounds were identified and further discussed, in light of reported literature, with different coffee characteristics: coffee ageing, organoleptic impact, presence of defective beans, authenticity, human's health implication, post-harvest coffee processing and roasting. The applied methodology showed to be a powerful analytical tool to be used for coffee characterization as it measures marker compounds of different coffee characteristics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.foodres.2018.02.072DOI Listing
May 2018

Determination of ammonia nitrogen in solid and liquid high-complex matrices using one-step gas-diffusion microextraction and fluorimetric detection.

Talanta 2017 May 3;167:747-753. Epub 2017 Feb 3.

REQUIMTE/LAQV - Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre no. 687, 4169-007 Porto, Portugal.

This paper introduces a new method for a one-step determination of ammonia nitrogen (NH) in high complex solid and liquid samples from the agricultural and livestock sectors. To this end, we developed a simultaneous extraction and fluorimetric labeling of NH, using gas diffusion microextraction (GDME), followed by the fluorescence measurement under 96-well microplate format. The GDME ensured a selective diffusion of NH through a commercial hydrophobic membrane, and confined the acceptor solution, which included the fluorimetric labeling reagent o-phthalaldehyde (OPA). The OPA-NH labeling reaction was optimized resorting to a full factorial experimental design, which showed that the reducing agent (NaSO) concentration was critical to achieve the highest sensitivity. A similar optimization approach for GDME showed that time and temperature significantly influenced the sensitivity of the assay, and also that the modifications in these two factors could be used to adjust the sensitivity according to the concentrations present in the samples. In our final conditions, it was possible to quantify NH in the range between 0.38 and 6.27mgL using a 10min extraction at 25°C in different samples (e.g., corn and grass silages, feces, urine). The developed method showed a high repeatability and reproducibility (intraday and interday relative standard deviations values of 4.5% and 9.5%, respectively) and an adequate limit of detection (0.22mgL). This new methodology also highlighted the simplicity and versatility of GDME for the determination of volatile components of high-complex matrices, which will certainly drive future developments in the analysis of environmental and biological samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2017.01.091DOI Listing
May 2017

Gas-diffusion microextraction coupled with spectrophotometry for the determination of formaldehyde in cork agglomerates.

Anal Bioanal Chem 2017 Apr 11;409(11):2885-2892. Epub 2017 Feb 11.

REQUIMTE/LAQV - Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007, Porto, Portugal.

In this work, a simple methodology was developed for the extraction and determination of free formaldehyde content in cork agglomerate samples. For the first time, gas-diffusion microextraction was used for the extraction of volatile formaldehyde directly from samples, with simultaneous derivatization with acetylacetone (Hantzsch reaction). The absorbance of the coloured solution was read in a spectrophotometer at 412 nm. Different extraction parameters were studied and optimized (extraction temperature, sample mass, volume of acceptor solution, extraction time and concentration of derivatization reagent) by means of an asymmetric screening. The developed methodology proved to be a reliable tool for the determination of formaldehyde in cork agglomerates with the following suitable method features: low LOD (0.14 mg kg) and LOQ (0.47 mg kg), r  = 0.9994, and intraday and interday precision of 3.5 and 4.9%, respectively. The developed methodology was applied to the determination of formaldehyde in different cork agglomerate samples, and contents between 1.9 and 9.4 mg kg were found. Furthermore, formaldehyde was also determined by the standard method EN 717-3 for comparison purposes; no significant differences between the results of both methods were observed. Graphical abstract Representation of the GDME system and its main components.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00216-017-0233-xDOI Listing
April 2017

An Insight on Salting-out Assisted Liquid-Liquid Extraction for Phytoanalysis.

Phytochem Anal 2017 Jul 26;28(4):297-304. Epub 2017 Jan 26.

REQUIMTE/LAQV - Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.

Introduction: Salting-out assisted liquid-liquid extraction (SALLE) is a technique that, although simple and not requiring any complex equipment, is very powerful and versatile. It has obtained growing interest in bioanalysis particularly when combined with chromatographic techniques.

Objectives: Herein, fennel seeds (Foeniculum vulgare Mill.) were used as a case-study to show the application of SALLE in phytochemical analysis.

Material And Methods: SALLE combined with HPLC-UV-MS/MS and GC-MS.

Results: By HPLC-UV-MS/MS analysis of the organic extract it was possible to identify various phenolic compounds, including quercetin derivatives, caffeic acid, p-coumaric acid and chlorogenic acid. The main compounds identified by GC-MS were estragole, fenchone, anisaldehyde, anethole, benzaldehyde, camphor and apiole.

Conclusion: HPLC and GC analysis of the extracts showed that it is possible to isolate, in only one step, a wide range of compounds with distinct properties, allowing a detailed phytochemical analysis. Copyright © 2017 John Wiley & Sons, Ltd.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/pca.2676DOI Listing
July 2017

Isolation of Cells Specialized in Anticancer Alkaloid Metabolism by Fluorescence-Activated Cell Sorting.

Plant Physiol 2016 08 29;171(4):2371-8. Epub 2016 Jun 29.

CIBIO/InBIO-Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal (S.B., T.M.-C., J.G.G., M.S.); Instituto de Investigação e Inovação em Saúde, Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal (I.C., A.L.G., P.D.);Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto, Portugal (I.C., M.S.);Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal (R.G., T.L., C.A., C.B., N.P.M.);REQUIMTE/Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal (P.A., P.V.); andREQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal (I.M.V., J.A.R.)

Plant specialized metabolism often presents a complex cell-specific compartmentation essential to accomplish the biosynthesis of valuable plant natural products. Hence, the disclosure and potential manipulation of such pathways may depend on the capacity to isolate and characterize specific cell types. Catharanthus roseus is the source of several medicinal terpenoid indole alkaloids, including the low-level anticancer vinblastine and vincristine, for which the late biosynthetic steps occur in specialized mesophyll cells called idioblasts. Here, the optical, fluorescence, and alkaloid-accumulating properties of C. roseus leaf idioblasts are characterized, and a methodology for the isolation of idioblast protoplasts by fluorescence-activated cell sorting is established, taking advantage of the distinctive autofluorescence of these cells. This achievement represents a crucial step for the development of differential omic strategies leading to the identification of candidate genes putatively involved in the biosynthesis, pathway regulation, and transmembrane transport leading to the anticancer alkaloids from C. roseus.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1104/pp.16.01028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4972299PMC
August 2016

Chromatographic analysis of methylglyoxal and other α-dicarbonyls using gas-diffusion microextraction.

Analyst 2013 Dec;138(23):7233-7

REQUIMTE - Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal.

Many α-dicarbonyl compounds such as methylglyoxal, diacetyl and pentane-2,3-dione are important quality markers of processed foods. They are produced by enzymatic and chemical processes, the Maillard reaction is the most known chemical route for α-dicarbonyl formation. In the case of methylglyoxal, there are obstacles to be overcome when analysing this compound due to its high reactivity, low volatility and low concentration. The use of extraction techniques based on the volatilization of methylglyoxal (like solid-phase microextraction) showed to be ineffective for the methylglyoxal extraction from aqueous solutions. Therefore, derivatization is typically applied to increase analyte's volatility. In this work a new methodology for the extraction and analysis of methylglyoxal and also diacetyl and pentane-2,3-dione from selected food matrices is presented. It is based on a gas-diffusion microextraction step followed by high performance liquid chromatographic analysis. It was successfully applied to port wines, black tea and soy sauce. Methylglyoxal, diacetyl and pentane-2,3-dione were quantified in the following concentration ranges: 0.24-1.74 mg L(-1), 0.1-1.85 mg L(-1) and 0.023-0.15 mg L(-1), respectively. The main advantages over existing methodologies are its simplicity in terms of sample handling, not requiring any chemical modification of the α-dicarbonyls prior to the extraction, low reagent consumption and short time of analysis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c3an00766aDOI Listing
December 2013

New application of the QuEChERS methodology for the determination of volatile phenols in beverages by liquid chromatography.

J Chromatogr A 2013 Jan 19;1271(1):27-32. Epub 2012 Nov 19.

REQUIMTE - Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, no. 687, 4169-007 Porto, Portugal.

The QuEChERS methodology has been used for the determination of pesticides in solid samples. However, this technique can be equally useful for other applications, namely for liquid samples. This work presents a new application of QuEChERS to the analysis of important ageing markers in beverages, the volatile phenols, by liquid chromatography with fluorimetric and UV detection. The sample preparation methodology comprises two sequential steps: (1) salting-out liquid-liquid extraction and (2) dispersive solid-phase extraction for extract clean-up. The methodology showed good repeatability (ca. 3%) and reproducibility (ca. 6%) with recovery levels above 90% and limits of detection varied in the range of 0.001-0.055 mg L(-1). A variable amount of phenols was found in the analysed samples (beers, wines and fruit juices), being 4-ethylphenol and 4-ethylguaiacol the compounds found in higher amounts, varying in the range of 0.12-1.11 mg L(-1) and 0.13-1.23 mg L(-1), respectively.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chroma.2012.11.026DOI Listing
January 2013

Application of gas-diffusion microextraction to the analysis of free and bound acetaldehyde in wines by HPLC-UV and characterization of the extracted compounds by MS/MS detection.

Anal Bioanal Chem 2012 May 29;403(4):1031-7. Epub 2011 Dec 29.

REQUIMTE-Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.

In wines, the presence of high levels of acetaldehyde (AA) not only is responsible for undesirable characteristic odours but can also cause health adverse effects. Such sensorial activity of AA can be overcome by adding sulphites during winemaking, due to the formation of adducts between AA and sulphites, which lower the sensorial impact of AA. Nevertheless, bound AA can be released during wine storage; therefore, the knowledge of its total amount can be important to estimate the long-term wine quality. The proposed methodology is based on the extraction of AA from wines using gas-diffusion microextraction and determination by liquid chromatography. Free and bound forms of AA could be differentiated and determined using an alkaline hydrolysis step to dissociate the sulphites-AA adducts. This methodology was successfully applied to different wine types, with free AA values ranging between 5 and 26 mg L(-1) and total form between 154 and 906 mg L(-1). Bound AA was above 90% of the total content determined for all samples analysed, and higher amounts were obtained for white wines (around 98%). Other carbonyl compounds were also identified in the extracts using mass spectrometry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00216-011-5664-1DOI Listing
May 2012

Analysis of cardamonin by square wave voltammetry.

Phytochem Anal 2012 Jul-Aug;23(4):396-9. Epub 2011 Oct 24.

Requimte, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre No. 687, 4169-007 Porto, Portugal.

Introduction: Several biochemical studies have already shown that cardamonin has health promoting properties, such is in agreement with typical characteristics of chalcones. Although being a very promising compound for the nutraceutical field there is a lack of studies concerning its electroanalytical properties.

Objective: To develop an electroanalytical methodology for the quantification of cardamonin in cardamom.

Methodology: Cardamonin was analysed electrochemically by means of a hanging mercury drop electrode (HMDE) using square wave voltammetry (SWV). It was extracted from cardamom spice and quantified thereafter using the standard additions method to overcome matrix effects.

Results: A limit of detection (LOD) of 0.15 mg/L and good linearity (r²  = 0.9998) were obtained. Decoction using ethanol as the extraction solvent appears to be the simplest extraction technique. Spectrophotometric analysis (maximum absorbance peak was found in ethanol at 344 nm with a value of molar extinction coefficient of (2.8 ± 0.1) × 10⁴  L mol⁻¹ cm⁻¹) and mass spectrometry analysis by electrospray in the positive ion mode were also performed.

Conclusion: Cardamonin was detected voltammetrically. The LOD and limit of quantification (LOQ) of the proposed voltammetric methodology are adequate for trace analysis of this compound in several phytochemical matrices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/pca.1370DOI Listing
October 2012

Increased sensitivity of anodic stripping voltammetry at the hanging mercury drop electrode by ultracathodic deposition.

Anal Chim Acta 2011 Sep 22;701(2):152-6. Epub 2011 Jun 22.

Requimte-Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, no. 687, 4169-007 Porto, Portugal.

An improved approach to the anodic stripping voltammetric (ASV) determination of heavy metals, using the hanging mercury drop electrode (HMDE), is reported. It was discovered that using very cathodic accumulation potentials, at which the solvent reduction occurs (overpotential deposition), the voltammetric signals of zinc(II), cadmium(II), lead(II) and copper(II) increase. When compared with the classical methodology a 5 to 10-fold signal increase is obtained. This effect is likely due to both mercury drop oscillation at such cathodic potentials and added local convection at the mercury drop surface caused by the evolution of hydrogen bubbles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.aca.2011.05.031DOI Listing
September 2011

Novel application of square-wave adsorptive-stripping voltammetry for the determination of xanthohumol in spent hops.

J Agric Food Chem 2011 Jul 21;59(14):7654-8. Epub 2011 Jun 21.

Departamento de Química e Bioquímica, Universidade do Porto, Porto, Portugal.

This paper reports the development of a novel electrochemical assay for xanthohumol (XN) by square-wave adsorptive-stripping voltammetry (SWAdSV) with a hanging mercury drop electrode. The method showed good repeatability (CV < 2%) and linearity (between 10 and 250 μg L(-1)), as well as suitable limits of detection (2.6 μg L(-1)) and quantification (8.8 μg L(-1)). The method was applied for the quantification of this compound in spent hops, and the results obtained were compared with the HPLC-UV method. XN contents determined by the SWAdSV method were 16 ± 1 and 100 ± 4 μg L(-1) for aqueous and methanolic extracts, respectively. The developed new methodology considerably reduces the analysis time, approximately from 25 min (HPLC-UV method) to 7 min, enabling a high sample throughput. In addition, the detection and quantification limits were approximately 5-fold lower than those obtained with the chromatographic method.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jf2011485DOI Listing
July 2011
-->